Arc-light electrode.



No. 859,579. PATENTED JULY 9; 1907'.

R. H. READ.

ARC LIGHT ELECTRODE. APPLIUATION FILED MAY 18, 1901:. RENEWED JUNE 16, 1907.

Witnesses Inventor Robert H. Read.

UNITED sirarrns rrrnri'fr. erosion.

ROBERT H. READ, OF SGHENEOTADY, NEW YOIlK, ASSXGN -JR TO GENERAL ELECTRIC COMPANY, A CORPORATION Oi. NEtVYORK.

lino-mom ELECTRODE.

Specification of Letters Patent.

Patented July 9, 1907.

Application filed May 18,1901. Renewed June 15,1907. Serial No. 379,112.

lo all whom it may concern:

Be. itkuown that 1, ROBERT H. READ, a citizen oi.

certain new and useful Improvements in Arc-Light l llectrodes, of which the following is a specification.

This invention relates to are lighting, the object being to improve the quality of the light and permit the main tenance of a longer are with currents of moderate potential and amyxrragc.

l have discovered that conducting electrodes for are lamps formed oi the conducting carbids or containing a. considerable portion of the same, permit it much longer are to be drawn with the some potential and current than corrospomling electrodes of carbon. The uction of the arc is also much smootlu-r than a carbon are, being rcmarlmbly quiet, the tendency of the tips I at the arc terminals being to fuse slightly before being vaporized, thus conduciug toward a quiet action free from hissing or dccrcpitation and much more stable than acurbon arc; The color ol the light varies with the base of the carbid. tor cxumplc, an arc containing cnrbid oi calcium has a rich golden color of intense luminosity, whereas, one formed of or containing aluminium carbid has a much whiter appeurance, the spcctriun varying with the nature of the carbid.

I prefer to employ carbids which are unaffected by moisture and therefore do not deteriorate in service when exposed to the atmosphere. For example, curbid of calcium is unsatisfactory for practical service unless mixed with a conducting bond or compound which protects each particle of the cur-bid from access of moisture. Whereas, aluminium carbid which is unaffected by moisture at ordinary temperatures does not require such protection. The present application covers the letter form of the invention, claims for conducting carbids in general, as well its for such carbide as are affected by moisture or require protection against the some, being made in s companion up plicution which is a division hereof, filed Oct. 25, 1902, Serial No. 128,786. Claims for other special carbids are made in other divisional cases, as titanium carbid; see application Serial No. 126,669, filed Oct. ll), 1.902.

Where carbide of lithium, calcium, strontium, barium, lanthanum, yttrium, thorium and manganese, or generally, any corbid which is attachable by cold Water is employed, the electrode should be formed of n mixture of ground cnrbid mixed with coal-tar, or similsir carbonaceousbindefbakecl and raised to inc-aw dsscen-Jze out of contact with air, and then paraiiined or similarly protected on the outside irom moisture; or such compounds may be employed as a core for hollow carbon. lf cored electrodes arr employed care should be observed to protect the core from access of moisture by coating the carbon with parollln or metal or other moisture-proof material, as the affinity ofsuch carbide as are decomposed by cold Water is so strong that moisture is absorbed through the pores of the carbon and soon splits the electrode along its axis. Much more satisfactory results may, lmwover, besecured by the carbids of aluminium, chromium, Zirconium, inolylod enum, titanium, Wolfram, which are not attacked by water at ordinary temperatures or at least very slightly so. I find that curbidoi aluminium gives excellent results either when employed pure or when mixed with n carbonizable binder, molded, and

baked; and by reason of its chenpness and ease of-manulecture is most fcasible for ordinary uses. It may also be used for score for n cored carbon. In preparing the electrodes, the material as produced in the electric furnace is finely pulverized and molded in sticks of the desired size by mixing witlrit about 5% of 2t carbonin able binder such as cane sugar or whent flour, moistened with n small quumity of coal-tar or even cold water. After drying and baking at n bright red heal, its structure may be rendered more compact and dense by filling, the pores with carbon by any approved process such for cxmnple as snturiuing with sugar and again firing or by raising to a red beat in a hyrlro-cnrbou vapor. When burning in an zuuoumtic lump it is desirable to provide for it slight lateral or scraping motion in drawing the arc to rub away the deposit oi oxid liable to form at the tips oi the clecirodes which a. good nonconductor ol' electricity. The lateral movement rubs off the thin film of oxid and gives u conduct ive connection which permits the arc to be struck, alter which it is maintained with more stability llmn on are between simple carbon electrodes, A proportional admixture of lire carblds with carbon also improves the nature of the light and the stability of the arc.

l find that a comparatively long arc may be maintained with mueh siualler current when the electrodes are composed. of or contain lhe conducting carbids as above described. The vapor acts as a better conductor and. seems to form a thicker-.u'c with the some cur rent than carbon, and the material when cold is u sulliciently good conductor to act as a car or of current. When used with an incluslng globe, the lamp in which theelectrodcs are used should be provided with a wiper for periodically removing the deposit from the walls oi the globe or this may be effected by providing a draft through the iuclosing globe; the latter expedient however, greatly reduces the lilo of the electrodes and in-' creases the expense of imtintenance. l lindthat with electrodes of carbid of calcium or curbid of aluminium, for example, a. good are from ;lto inches in length may be maintained by a current of one ampere with a drop across the are of 50 volts, thus giving an energy cousuinptionof 50 watts per unit of light, and yielding a brilliant, steady and uniform light.

In the accompanying drawings; Figures 1 and 2 illustrate elevations of are light pencils of different sizes formed according to my invention. Y Fig. 3 shows a. cored electrode. They may consist of sawed sticks oi a crystalline carbid or may be composed of a carbonized compound of the carbid and the carbonaceous material as zibove set forth; 1 representing an electrode suitable for 215 ainpere larnp and 2 one suitable for a one ampere ramp, 3 represents a hollow carbon pencil and 4 a core of conducting carbid compound as above described.

Novel features of my invention disclosed but not claimed herein are claimed in the following applicalions tiled by me as divisions of the present application, to witapplications, Serial 120,669, are light. Serial l28,786,arc light electrode. Serial #262757, are light electrode.

W hat I claim as new and desire to secure by Letters Patent of the United States, is, I

1. Au are-light electrode containing a conducting chrllid insensitive to moisture.

2. An arc-light electrode containing cnrbid of aluminiuni.

An arc-light electrode composed of tinelyflivided alu minium can-hid united by it carbonaceous binder.

4. An arc light electrode composed principally of a conducting cur-bid insensitive to moisture.

In witness whereof 1.11:1ve hereunto set my hand this 1am day of May, 1001.

BnxJAuix B HULL, Ahmmurr I Woonnm'. 

